Wireless transmission system, control method, and storage medium

ABSTRACT

A second transmission path coupler has such a size that a signal width of a first signal that is generated by the second transmission path coupler at timings corresponding to a rising edge and a falling edge of an input signal to be input to a first transmission path coupler in a case where the input signal is transmitted to a position at which the first transmission path coupler and the second transmission path coupler perform an electric field and/or magnetic field coupling is substantially equal to or greater than a difference in a transmission delay amount corresponding to a gap of the first transmission path coupler.

BACKGROUND Field

The present disclosure relates to a wireless transmission systemincluding a movable transmission path.

Description of the Related Art

A technique for controlling an apparatus that includes a rotatablemovable portion, such as a robot hand portion or a network camera,through communication via a network or the like has been underdevelopment. The apparatus including such a rotatable movable portioncan be configured to perform data communication through the rotatablemovable portion in order to prevent issues such as a cable becomingentangled around a shaft while the rotatable movable portion is rotated.

Japanese Patent Application Laid-Open No. 4-45505 discusses aconfiguration in which an electric signal is input from one end of aring-shaped first transmission path and the other end of the firsttransmission path is terminated, and a signal output from a secondtransmission path that is opposed to the first transmission path isdetected. In this case, if the electric signal is input from a first endof the first transmission path and is transmitted to a second end of thefirst transmission path, a timing when the electric signal reaches thefirst end deviates from a timing when the electric signal reaches thesecond end. In other words, the electric signal reaches the second endwith a delay with respect to the first end due to a transmission delayon the first transmission path. Accordingly, on the second transmissionpath, the signal reception timing varies depending on which part of thefirst transmission path the signal is received from. To address this,Japanese Patent Application Laid-Open No. 4-45505 discusses a techniquefor correcting a signal timing deviation depending on the position ofthe second transmission path using a variable delay unit that isconnected to the second transmission path. Specifically, when the secondtransmission path is located near the first end of the firsttransmission path, the delay amount of the variable delay unit isincreased, and when the second transmission path is located near thesecond end of the first transmission path, the delay amount of thevariable delay unit is decreased.

However, according to the technique discussed in Japanese PatentApplication Laid-Open No. 4-45505, as illustrated in FIG. 6A, a gapbetween a first end A for inputting a signal from a first transmissionpath 101 and a terminated second end B is small. Accordingly, a secondtransmission path 111 can be opposed to both the first end A and thesecond end B of the first transmission path 101. FIG. 6B illustrates anedge signal of an input signal detected by the second transmission path111 (reception coupler). When the second transmission path 111 is movedabove the first end A and the second end B of the first transmissionpath 101, signals that are output from the first end A and the secondend B of the first transmission path 101 at different timings arecombined as illustrated in FIG. 6B. Accordingly, temporal “skipping”occurs in the signal output from the second transmission path, and ifthe temporal “skipping” exceeds a permissible jitter amount of a digitalcircuit, erroneous data may be output.

To address the above-described issue, Japanese Patent ApplicationLaid-Open No. 2015-202415 discusses a method for establishing a stablecommunication while preventing data skipping by appropriately selectingand switching a plurality of sending-side transmission paths (sendcoupler) and receiving-side transmission paths (reception coupler).

However, in the method discussed in Japanese Patent ApplicationLaid-Open No. 2015-202415, there is a need for routing an input channelsignal to (N+1) transmission lines through a delay unit depending on aposition of a rotatable movable portion relative to a fixed portion.Accordingly, a relative position detection unit and a switch unit forswitching the input signal at a high speed are required, and thus theconfiguration thereof becomes complicated.

SUMMARY

In view of the above-described issues, various embodiments of thepresent disclosure are directed to preventing destabilization ofcommunication with a simple configuration when signals are transmittedusing a first transmission path coupler including a gap and a secondtransmission path coupler that is opposed to the first transmission pathcoupler in a non-contact state.

According to one embodiment of the present disclosure, a wirelesstransmission system includes a first transmission path coupler includingtransmission lines configured to transmit a signal, one end of each ofthe transmission lines being connected to a send unit, another end ofeach of the transmission lines being connected to a terminatingresistor, the first transmission path coupler being annularly disposed,and a second transmission path coupler including transmission linesconfigured to transmit a signal, one end of each of the transmissionlines being connected to a comparator, another end of each of thetransmission lines being connected to a terminating resistor, the secondtransmission path coupler being configured to be moved across a gap ofthe first transmission path coupler. The second transmission pathcoupler generates a first signal at timings corresponding to a risingedge and a falling edge of an input signal input to the firsttransmission path coupler in a case where the input signal istransmitted to a position at which the first transmission path couplerand the second transmission path coupler perform an electric fieldand/or magnetic field coupling, a signal width of the first signal beingsubstantially in proportion to a length of the electric field and/ormagnetic field coupling of the first transmission path coupler and thesecond transmission path coupler. The signal width of the first signalis substantially equal to or greater than a difference in a transmissiondelay amount of the first transmission path coupler.

Further features of the present disclosure will become apparent from thefollowing description of example embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a configuration example of a system according to afirst example embodiment.

FIGS. 2A and 2B are timing diagrams used to determine the size of areception coupler according to the first example embodiment.

FIGS. 3A and 3B are timing diagrams illustrating a case where thereception coupler according to the first example embodiment is movedalong the circumference of a send coupler.

FIG. 4 illustrates a configuration example of a system according to asecond example embodiment.

FIG. 5 illustrates a configuration example of another system accordingto the second example embodiment.

FIG. 6A is a configuration diagram for illustrating a system accordingto a related art, and FIG. 6B is a timing diagram of the systemaccording to the related art.

FIG. 7 is a system configuration diagram used to explain a principlecommon to the example embodiments.

FIG. 8 depicts four timing diagrams (A) through (D) that are used toexplain a principle common to the example embodiments.

FIG. 9 is another system configuration diagram used to explain theprinciple common to the example embodiments.

DESCRIPTION OF THE EMBODIMENTS

Example embodiments of the present disclosure will be described indetail below with reference to the accompanying drawings. It will beunderstood that components described in the following exampleembodiments are merely example features, and the present invention isnot limited to the illustrated components.

Initially, a principle common to example embodiments of the presentdisclosure will be described. FIG. 7 is a system configuration diagramfor illustrating the principle common to the example embodiments. Atransmission path coupler 101 includes a pair of signal lines and servesas a sending-side transmission path coupler for differential signals.The transmission path coupler 101 is hereinafter referred to as a sendcoupler 101. Data transmitted from a signal source 103 (transmissionunit) that is connected to the send coupler 101 is input to the sendcoupler 101 as differential signals through a differential send buffer104 that is connected to the signal source 103 (hereinafter alsoreferred to as a differential buffer 104). An end of the send coupler101 that is opposite to the end connected to the signal source 103 isterminated by a terminating resistor 102 that is substantially equal toa transmission path characteristic impedance.

A transmission path coupler 111 includes a pair of signal lines andserves as a receiving-side transmission path coupler for differentialsignals. The transmission path coupler 111 is hereinafter referred to asthe reception coupler 111. The reception coupler 111 is movable alongthe send coupler 101. The reception coupler 111 is coupled to the sendcoupler 101 by an effect of at least one of an electric field and amagnetic field. An input signal input from the signal source 103 isoutput from one end of the reception coupler 111 to a waveform shapingcircuit 113 through an electric field and/or magnetic field couplingbetween the send coupler 101 and the reception coupler 111. The waveformof the input signal is shaped by the waveform shaping circuit 113, andthe input signal is detected as a received signal. The other end of thereception coupler 111 is terminated by a terminating resistor 112 thatis substantially equal to the transmission path characteristicimpedance.

The send coupler 101 and the reception coupler 111 each operate as adirectional coupler. An end of the reception coupler 111 thatcorresponds to the end of the send coupler 101 that is connected to thesignal source 103 is referred to as a coupled end, and the other end ofthe reception coupler 111 is referred to as an isolation end.

FIG. 8 depicts four timing diagrams (A) though (D) illustrating aprinciple common to the example embodiments. Timing diagram (A) of FIG.8 illustrates a signal that is output from the signal source 103, i.e.,a signal that is input to the send coupler 101. Timing diagram (B) ofFIG. 8 illustrates a signal that is output from the send coupler 101 ata position opposed to the reception coupler 111. Timing diagram (C) ofFIG. 8 illustrates a signal that is output from the coupled end in acase where the isolation end of the reception coupler 111 is terminatedand the signal is output from the coupled end. Timing diagram (D) ofFIG. 8 illustrates a signal that is output from the waveform shapingcircuit 113.

As illustrated in the timing diagrams (A)-(D) of FIG. 8, the signaltransmitted through the send coupler 101 and the signal detected by thereception coupler 111 are differential signals. However, for simplicityof illustration, the differential signals are illustrated assingle-ended signals corresponding to the differential signals.

The signal output from the signal source 103, as illustrated in timingdiagram (A) of FIG. 8, is input to the send coupler 101 through thedifferential buffer 104. The signal transmitted on the send coupler 101is transmitted at a transmission mode speed on a substrate, and isabsorbed in the terminating resistor 102, which is substantially equalto the characteristic impedance of the send coupler 101.

Here, if the terminating resistor 102 completely matches thecharacteristic impedance of the send coupler 101, the signal transmittedat a terminal end is not reflected and is absorbed in the terminatingresistor 102.

In such a case, the signal, on the send coupler 101, at the positionopposed to the reception coupler 111 becomes the signal as illustratedin timing diagram (B) of FIG. 8. The signal as illustrated in timingdiagram (B) of FIG. 8 lags behind the input signal by a period Ali,which is the sum of a delay in the differential buffer 104 and atransmission delay.

The signal detected by the reception coupler 111, as illustrated intiming diagram (C) of FIG. 8, rises in response to a rising edge of thesignal illustrated in timing diagram (B) of FIG. 8, and then the risingedge of the signal illustrated in timing diagram (C) of FIG. 8 is heldfor a period that is substantially in proportion to the length of theelectric field and/or magnetic field coupling between the send coupler101 and the reception coupler 111. In other words, the rising edge ofthe signal illustrated in timing diagram (C) of FIG. 8 is held for aperiod that is substantially in proportion to the length of thereception coupler 111. In this case, the rising edge of the signalillustrated in timing diagram (C) of FIG. 8 is held for a period tonwhich is substantially in proportion to a length L1 of the receptioncoupler 111 illustrated in FIG. 7. After that, the signal illustrated intiming diagram (C) of FIG. 8 becomes substantially “0”.

Further, the signal illustrated in timing diagram (C) of FIG. 8 falls inresponse to a falling edge of the signal illustrated in timing diagram(B) of FIG. 8, and the falling edge of the signal illustrated in timingdiagram (C) of FIG. 8 is also held for the period ton. After that, thesignal illustrated in timing diagram (C) of FIG. 8 becomes substantially“0”.

The waveform shaping circuit 113 demodulates the input signal from theoutput signal from the reception coupler 111. The waveform shapingcircuit 113 is generally configured with a comparator provided with ahysteresis so that “1” is output when the signal illustrated in timingdiagram (C) of FIG. 8 (edge signal) detected by the reception coupler111 is more than or equal to a positive threshold voltage Vth and “0” isoutput when the signal illustrated in timing diagram (C) of FIG. 8 isless than or equal to a negative threshold voltage −Vth. The waveformshaping circuit 113 is hereinafter referred to as the comparator 113.

In the signal illustrated in timing diagram (C) of FIG. 8, a reflectedwave due to a small difference between the characteristic impedance ofthe send coupler 101 and the impedance of the terminating resistor 102,a reflected wave due to a mismatch in the reception coupler 111, and thelike may occur as noise signals. However, if the noise signals arewithin the range of the above-described threshold voltages (Vth, −Vth),an output of the waveform shaping circuit 113 does not vary depending onthe noise signal. The output of the waveform shaping circuit 113 variesdepending only on the rising edge and falling edge of the signalillustrated in timing diagram (C) of FIG. 8. Thus, the terminatingresistor 112 can demodulate the signal illustrated in timing diagram (D)of FIG. 8 that has the same waveform as the waveform of the signalillustrated in timing diagram (B) of FIG. 8.

While FIG. 7 illustrates an example where a long transmission path isused as the send coupler 101 and a short transmission path that ismovable along the long transmission path is used as the receptioncoupler 111, the present invention is not limited to this example. Sincethe directional coupler has reversibility, similar advantageous effectscan be obtained even when the send coupler 101 and the reception coupler111 are replaced as illustrated in FIG. 9. Each component included in asystem configuration diagram illustrated in FIG. 9 corresponds to thecomponent denoted by the same reference numeral in the systemconfiguration diagram illustrated in FIG. 7.

A first example embodiment of the present disclosure will be describednext. FIG. 1 illustrates a configuration example of a wirelesstransmission system according to the present example embodiment. In thewireless transmission system according to the present exampleembodiment, the send coupler 101 is annularly disposed on thecircumference of a circle. The reception coupler 111 is configured to bemoved on the circumference of the circle along the send coupler 101. Thereception coupler 111 outputs a signal from the coupled end.

In a case where the wireless transmission system according to thepresent example embodiment is disposed in an apparatus including arotatable member, the send coupler 101 is disposed on the circumferenceof a circle about a rotational axis of the rotatable member. Thereception coupler 111 is disposed such that the reception coupler 111 isopposed to the send coupler 101 and is movable on the circumference ofthe circle about the rotational axis of the rotatable member. Thereception coupler 111 may be disposed on the outside or inside of therotatable member. The send coupler 101 and the reception coupler 111communicate signals through the electric field and/or magnetic fieldcoupling. In FIG. 1, the illustration of members such as a substratethat supports the send coupler 101 and the reception coupler 111, andground conductors used when differential high-frequency transmissionpaths, such as microstrip lines or coplanar lines, are used as the sendcoupler 101 and the reception coupler 111 is omitted to simplify thedescription.

FIG. 1 illustrates a configuration example in which the transmissionpath coupler 101 functions as a send coupler and the transmission pathcoupler 111 functions as a reception coupler. However, the presentinvention is not limited to this example. The transmission path coupler101 may function as a reception coupler and the transmission pathcoupler 111 may function as a send coupler.

The send coupler 101 and the reception coupler 111 may be included inthe same apparatus, or may be included in different apparatuses.

In a case where an output signal obtained from the reception coupler 111is smaller than a desired signal level, an amplifier may be disposedbetween the reception coupler 111 and the comparator 113.

The send coupler 101 is a transmission path including a pair ofconductors and is annularly disposed on the circumference of a circle.The send coupler 101 has a gap. One end of the send coupler 101 isconnected to the signal source 103 through the differential buffer 104.The other end of the send coupler 101 is connected to the terminatingresistor 102. A signal output from the signal source 103 is transmittedtoward the terminating resistor 102 via the send coupler 101, and flowsinto the terminating resistor 102.

The reception coupler 111 is disposed such that the reception coupler111 is opposed to the send coupler 101 on the circumference of thecircle having the same center as that of the circumference on which thesend coupler 101 is disposed. The reception coupler 111 is also atransmission path including a pair of conductors, and is formed with alength shorter than the send coupler 101. The reception coupler 111 isdisposed such that the reception coupler 111 can be coupled to the sendcoupler 101 through the electric field and/or magnetic field coupling,and is configured to generate a signal based on an electric signalflowing through the send coupler 101.

The isolation end of the reception coupler 111 is terminated by theterminating resistor 112. The coupled end of the reception coupler 111is connected to the comparator 113. The comparator 113 shapes thewaveform of the signal received by the reception coupler 111, andtransmits the signal to a digital circuit 114 which is connected to thecomparator 113.

Here, the gap of the send coupler 101 is formed with a size that issmaller than the size of the reception coupler 111. When the receptioncoupler 111 is opposed to the send coupler 101 with the gap interposedtherebetween, the reception coupler 111 is electric-field and/ormagnetic-field coupled to the both ends of the send coupler 101 at thesame time. In this case, the reception coupler 111 receives both asignal with almost no delay from the input signal that is input to thesend coupler 101, and a signal that lags behind the input signal due toa transmission delay on the send coupler 101. The reception coupler 111receives a signal obtained by combining these two signals according tothe ratio of coupling between the reception coupler 111 and thetransmission paths at two ends of the send coupler 101.

FIGS. 2A and 2B are timing diagrams used to determine the size of thereception coupler 111. FIG. 2A illustrates a waveform of an input signalV(in) input to the send coupler 101, a waveform of a signal V(term)output from the terminal end of the send coupler 101, and a waveform ofan output signal output from the coupled end of the reception coupler111 for each angle of the arc of the reception coupler 111 in this orderfrom top. FIGS. 2A and 2B illustrate the waveform of the output signalwhen the angle of the arc of the reception coupler 111 is 160 degrees,170 degrees, 180 degrees, 190 degrees, and 200 degrees. When the angleof the arc of the reception coupler 111 is more than or equal to 180degrees of the circumference of the circle, the signal width of theoutput signal from the reception coupler 111 is greater than a delaytime of the signal V(term) with respect to the input signal of the sendcoupler 101, so that the output signal from the reception coupler 111has no discontinuity.

In the reception coupler 111 according to the present exampleembodiment, when the angle of the arc of the reception coupler 111 is160 degrees or more and less than 180 degrees, the discontinuity of thereceived signal is 0.1 nanoseconds (ns) or less. Thus, since there arealmost no comparators that can respond to such a small discontinuity,the output signal from the comparator 113 has no discontinuity.

Here, if a signal is transmitted at a speed of, for example, 1 Gbps, themaximum basic frequency of the signal is 500 MHz. On the other hand, ifthe received signal has a discontinuity of 0.1 ns, the basic frequencycomponent of the signal is 5 GHz. In such a case, a low-pass filter(LPF) which passes the basic frequency of the signal and controlsfrequency components at the discontinuity is disposed between thereception coupler 111 and the comparator 113, thus preventing theoccurrence of a discontinuity in the output signal from the comparator113 even when the discontinuity is present. To simplify theconfiguration, a capacitor of about a few pH may be disposed as the LPFin parallel between the outputs of differential transmission paths ofthe reception coupler 111 to filter the signal. In this case, thediscontinuity of the signal is decreased, so that no discontinuityoccurs in the output signal from the comparator 113 even when the angleof the arc is less than or equal to 180 degrees. Similarly, if themaximum frequency at which the comparator 113 can respond is higher thanthe maximum basic frequency of the signal and is lower than thefrequency component at the discontinuity, no discontinuity occurs in theoutput signal from the comparator 113.

The occurrence of a discontinuity in the signal can be preventeddepending on the LPF disposed or the maximum response frequency of thecomparator 113. However, when the reception coupler 111 is moved abovethe gap of the send coupler 101, a phase shift occurs in the receivedsignal. This phase shift is to be prevented from exceeding a permissiblejitter amount of the digital circuit 114 that is connected to thereception coupler 111.

FIG. 2B is a timing diagram illustrating a case where the angle of thearc of the reception coupler 111 is 180 degrees of the circumference ofthe circle. FIG. 2B illustrates an input signal (A) that is input to thesend coupler 101, a signal (B) that is output from the terminal end ofthe send coupler 101, a signal (C) that is output from the receptioncoupler 111, and a signal (D) that is output from the comparator 113 inthis order from top.

As illustrated in FIG. 2B, the signal width ton of the signal (C) issubstantially equal to a delay amount td of the signal (B) with respectto the signal (A). Accordingly, it can be seen that the signal (D) hasno discontinuity. As seen from FIG. 2B, data skipping in the signaloutput from the comparator 113 is controlled by appropriately settingthe size of the reception coupler 111.

FIGS. 3A and 3B are timing diagrams illustrating a case where thereception coupler 111 is moved along the circumference of the sendcoupler 101. FIG. 3A illustrates a case where the angle of the arc ofthe reception coupler 111 is 150 degrees, and FIG. 3B illustrates a casewhere the angle of the arc of the reception coupler 111 is 180 degrees.

FIGS. 3A and 3B each illustrate an input signal that is input to thesend coupler 101, a signal that is output from the terminal end of thesend coupler 101, and an output signal that is output from the receptioncoupler 111 at each relative angle between the send coupler 101 and thereception coupler 111 in this order from top.

FIG. 3A illustrates the waveform of the output signal from the receptioncoupler 111 when the relative angle is −160 degrees, −130 degrees, −100degrees, −70 degrees, −40 degrees, −10 degrees, and 10 degrees. Thereception coupler 111 mainly receives signals in the vicinity of theterminal end of the send coupler 101 when the relative angle between thereception coupler 111 and the send coupler 101 is −130 degrees. In thiscase, the threshold voltages Vth and −Vth of the comparator 113 arereached at timings corresponding to a rising edge and a falling edgethat are affected by the delayed signal (signal at the terminal end) ofthe send coupler 101. Accordingly, the output signal from the comparator113 is output as the signal lagging behind the input signal that isinput to the send coupler 101.

The reception coupler 111 mainly receives signals in the vicinity of theend to which the signal from the send coupler 101 is input when therelative angle between the reception coupler 111 and the send coupler101 is −100 degrees. In this case, the output signal from the comparator113 is output with almost no effect of the signal (signal at theterminal end) with a delay due to a transmission delay on the sendcoupler 101. Accordingly, in a case where the relative angle between thereception coupler 111 and the send coupler 101 is changed from −130degrees to −100 degrees, the signal output from the comparator 113 ischanged from the signal that is affected by the signal with a delay dueto a transmission delay on the send coupler 101 to the signal that isnot affected by the signal. In this case, skipping occurs at timingscorresponding to a rising edge and a falling edge of the signal outputfrom the comparator 113.

In a case where the reception coupler 111 is reversely rotated withrespect to the send coupler 101, the angle of the reception coupler 111relative to the send coupler 101 is changed from −100 degrees to −130degrees. In this case, since the signal output from the comparator 113is changed from the signal that is not affected by the signal with adelay due to a transmission delay on the send coupler 101 to the signalthat is affected by the signal, skipping occurs at timings correspondingto a rising edge and a falling edge of the signal output from thecomparator 113.

FIG. 3B illustrates the waveform of the output signal from the receptioncoupler 111 when the relative angle is −190 degrees, −160 degrees, −130degrees, −100 degrees, −70 degrees, −40 degrees, —10 degrees, and 10degrees. As illustrated in FIG. 3B, the timings when the thresholds Vthand −Vth are exceeded in the case where the relative angle between thereception coupler 111 and the send coupler 101 is −130 degrees issubstantially equal to that in the case where the relative angle is −100degrees. Accordingly, even in a case where the relative angle betweenthe reception coupler 111 and the send coupler 101 is changed from −130degrees to −100 degrees, skipping does not occur at timingscorresponding to a rising edge and a falling edge of the signal outputfrom the comparator 113.

As described above, the size of the reception coupler 111 is set to besubstantially equal to the signal width of the signal output from thereception coupler 111 and the delay amount of the output signal at theterminal end with respect to the input signal to be input to the sendcoupler 101, thus preventing skipping in the signal output from thecomparator. Thus, data skipping on the receiving side can be prevented.

A second example embodiment of the present disclosure will be describedbelow. While the first example embodiment uses the system configurationas illustrated in FIG. 1, the present invention is not limited to thisconfiguration. The size of the reception coupler 111 can be determinedin a similar manner in system configurations other than theabove-described system configuration.

FIG. 4 illustrates a configuration example of a wireless transmissionsystem different from the wireless transmission system according to thefirst example embodiment. In the configuration example illustrated inFIG. 4, the send coupler 101 is disposed on a side surface of acylinder, and the reception coupler 111 is disposed on the outside ofthe cylinder such that the reception coupler 111 is opposed to the sendcoupler 101. In this system configuration, the reception coupler 111 hassuch a size that the signal width of the output signal from thereception coupler 111 is substantially equal to the delay amount of theoutput signal at the terminal end with respect to the input signal to beinput to the send coupler 101, as in the first example embodiment. Theconfiguration of the reception coupler 111 is not limited to thisconfiguration. The reception coupler 111 may be configured as a couplerhaving a size large enough to hold a signal for a long period of time.In the system illustrated in FIG. 4, the send coupler 101 formed in acylindrical shape includes differential transmission paths with the samelength, and thus the differential transmission paths are more easilyaligned in phase than in the system according to the first exampleembodiment, and the reflection at the terminal end can be reduced.

FIG. 5 illustrates a configuration example of another wirelesstransmission system different from the wireless transmission systemaccording to the first example embodiment.

Unlike the system illustrated in FIG. 4, the system illustrated in FIG.5 has a configuration in which the reception coupler 111 is disposed onthe inside of the send coupler 101. As in the system illustrated in FIG.4, the reception coupler 111 has such a size that the signal width ofthe output signal from the reception coupler 111 is substantially equalto the delay amount of the output signal at the terminal end withrespect to the input signal to be input to the send coupler 101.However, the configuration of the reception coupler 111 is not limitedto this configuration. The reception coupler 111 may be configured as acoupler having a size large enough to hold a signal for a long period oftime.

As described above, also in the system configuration illustrated in thesecond example embodiment, data skipping can be controlled byappropriately determining the size of the reception coupler 111, as inthe first example embodiment.

In a practical circuit, the digital circuit 114 includes a permissiblejitter amount tj. Accordingly, the reception coupler 111 may beconfigured to have such a size that skipping within a range smaller thanthe permissible jitter amount tj can occur. Specifically, it is onlyrequired that the delay amount td of the output signal at the terminalend with respect to the input signal to be input to the send coupler 101and the signal width ton of the output signal from the reception coupler111 satisfy tj<ton−td.

The wireless transmission systems according to the first and secondexample embodiments may be configured not only to communicate wirelesssignals, but also to transmit power. Instead of the transmission pathsfor sending and receiving differential signals according to the firstand second example embodiments, a single transmission line may be usedin other embodiments.

According to various embodiments of the present disclosure, it ispossible to prevent destabilization of communication with a simpleconfiguration when signals are transmitted using a first transmissionpath coupler including a gap and a second transmission path coupler thatis opposed to the first transmission path coupler in a non-contactstate.

Other Embodiments

Various embodiments of the present disclosure can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While example embodiments have been described, it is to be understoodthat the invention is not limited to the disclosed example embodiments.The scope of the following claims is to be accorded the broadestinterpretation so as to encompass all such modifications and equivalentstructures and functions.

This application claims the benefit of Japanese Patent Application No.2020-173313, filed Oct. 14, 2020, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A wireless transmission system comprising: afirst transmission path coupler including transmission lines configuredto transmit a signal, one end of each of the transmission lines beingconnected to a send unit, another end of each of the transmission linesbeing connected to a terminating resistor, the first transmission pathcoupler being annularly disposed; and a second transmission path couplerincluding transmission lines configured to transmit a signal, one end ofeach of the transmission lines being connected to a comparator, anotherend of each of the transmission lines being connected to a terminatingresistor, the second transmission path coupler being configured to bemoved across a gap of the first transmission path coupler, wherein thesecond transmission path coupler generates a first signal at timingscorresponding to a rising edge and a falling edge of an input signalinput to the first transmission path coupler in a case where the inputsignal is transmitted to a position at which the first transmission pathcoupler and the second transmission path coupler perform an electricfield and/or magnetic field coupling, a signal width of the first signalbeing substantially in proportion to a length of the electric fieldand/or magnetic field coupling of the first transmission path couplerand the second transmission path coupler, and wherein the signal widthof the first signal is substantially equal to or greater than adifference in a transmission delay amount of the first transmission pathcoupler.
 2. The wireless transmission system according to claim 1,wherein an angle of an arc of the second transmission path coupler ismore than or equal to 180 degrees and less than or equal to 200 degrees.3. The wireless transmission system according to claim 1, wherein thesecond transmission path coupler further includes a low-pass filterconnected to the second transmission path coupler, and wherein an angleof an arc of the second transmission path coupler is more than or equalto 160 degrees and less than 180 degrees.
 4. The wireless transmissionsystem according to claim 1, wherein the comparator shapes a waveform ofan input signal.
 5. The wireless transmission system according to claim4, wherein the comparator shapes the waveform by switching an outputdepending on whether the input signal is more than or equal to a firstthreshold or the input signal is less than or equal to a secondthreshold different from the first threshold.
 6. The wirelesstransmission system according to claim 1, wherein, in a case where thesecond transmission path coupler is opposed to the first transmissionpath coupler with the gap interposed therebetween, the secondtransmission path coupler receives a signal obtained by combining asignal without a delay behind the input signal input to the firsttransmission path coupler and a signal with a delay corresponding to atransmission on the first transmission path coupler behind the inputsignal input to the first transmission path coupler.
 7. A method forcontrolling a wireless transmission system, the wireless transmissionsystem comprising: a first transmission path coupler includingtransmission lines configured to transmit a signal, one end of each ofthe transmission lines being connected to a send unit, another end ofeach of the transmission lines being connected to a terminatingresistor, the first transmission path coupler being annularly disposed;and a second transmission path coupler including transmission linesconfigured to transmit a signal, one end of each of the transmissionlines being connected to a comparator, another end of each of thetransmission lines being connected to a terminating resistor, the secondtransmission path coupler being configured to be moved across a gap ofthe first transmission path coupler, the method comprising: generating,by the second transmission path coupler, a first signal at timingscorresponding to a rising edge and a falling edge of an input signalinput to the first transmission path coupler in a case where the inputsignal is transmitted to a position at which the first transmission pathcoupler and the second transmission path coupler perform an electricfield and/or magnetic field coupling, a signal width of the first signalbeing substantially in proportion to a length of the electric fieldand/or magnetic field coupling of the first transmission path couplerand the second transmission path coupler; and inputting the generatedfirst signal to the comparator, wherein the signal width of the firstsignal is substantially equal to or greater than a difference in atransmission delay amount corresponding to the gap of the firsttransmission path coupler.
 8. A non-transitory computer-readable storagemedium storing instructions that, when executed by a computer, cause thecomputer to perform a method for controlling a wireless transmissionsystem, the wireless transmission system comprising: a firsttransmission path coupler including transmission lines configured totransmit a signal, one end of each of the transmission lines beingconnected to a send unit, another end of each of the transmission linesbeing connected to a terminating resistor, the first transmission pathcoupler being annularly disposed; and a second transmission path couplerincluding transmission lines configured to transmit a signal, one end ofeach of the transmission lines being connected to a comparator, anotherend of each of the transmission lines being connected to a terminatingresistor, the second transmission path coupler being configured to bemoved across a gap of the first transmission path coupler, the methodcomprising: generating, by the second transmission path coupler, a firstsignal at timings corresponding to a rising edge and a falling edge ofan input signal input to the first transmission path coupler in a casewhere the input signal is transmitted to a position at which the firsttransmission path coupler and the second transmission path couplerperform an electric field and/or magnetic field coupling, a signal widthof the first signal being substantially in proportion to a length of theelectric field and/or magnetic field coupling of the first transmissionpath coupler and the second transmission path coupler; and inputting thegenerated first signal to the comparator, wherein the signal width ofthe first signal is substantially equal to or greater than a differencein a transmission delay amount corresponding to the gap of the firsttransmission path coupler.
 9. A wireless transmission system comprising:a first transmission path coupler including transmission linesconfigured to transmit a signal, one end of each of the transmissionlines being connected to a send unit, another end of each of thetransmission lines being connected to a terminating resistor, the firsttransmission path coupler being annularly disposed; and a secondtransmission path coupler including transmission lines configured totransmit a signal, one end of each of the transmission lines beingconnected to a comparator, another end of each of the transmission linesbeing connected to a terminating resistor, the second transmission pathcoupler being configured to be moved across a gap of the firsttransmission path coupler, wherein the second transmission path couplerfurther includes a circuit configured to control a frequency componentat a discontinuity of a signal that occurs when the second transmissionpath coupler is moved across the gap of the first transmission pathcoupler, and to pass a maximum basic frequency of a signal input to thefirst transmission path coupler.
 10. A method for controlling a wirelesstransmission system, the wireless transmission system comprising: afirst transmission path coupler including transmission lines configuredto transmit a signal, one end of each of the transmission lines beingconnected to a send unit, another end of each of the transmission linesbeing connected to a terminating resistor, the first transmission pathcoupler being annularly disposed; and a second transmission path couplerincluding transmission lines configured to transmit a signal, one end ofeach of the transmission lines being connected to a comparator, anotherend of each of the transmission lines being connected to a terminatingresistor, the second transmission path coupler being configured to bemoved across a gap of the first transmission path coupler, the secondtransmission path coupler further including a circuit configured tocontrol a frequency component at a discontinuity of a signal that occurswhen the second transmission path coupler is moved across the gap of thefirst transmission path coupler, and to pass a maximum basic frequencyof a signal input to the first transmission path coupler, the methodcomprising: generating, by the second transmission path coupler, a firstsignal at timings corresponding to a rising edge and a falling edge ofan input signal input to the first transmission path coupler in a casewhere the input signal is transmitted to a position at which the firsttransmission path coupler and the second transmission path couplerperform an electric field and/or magnetic field coupling, a signal widthof the first signal being substantially in proportion to a length of theelectric field and/or magnetic field coupling of the first transmissionpath coupler and the second transmission path coupler; and inputting thegenerated first signal to the comparator.
 11. A non-transitorycomputer-readable storage medium storing instructions that, whenexecuted by a computer, cause the computer to perform a method forcontrolling a wireless transmission system, the wireless transmissionsystem comprising: a first transmission path coupler includingtransmission lines configured to transmit a signal, one end of each ofthe transmission lines being connected to a send unit, another end ofeach of the transmission lines being connected to a terminatingresistor, the first transmission path coupler being annularly disposed;and a second transmission path coupler including transmission linesconfigured to transmit a signal, one end of each of the transmissionlines being connected to a comparator, another end of each of thetransmission lines being connected to a terminating resistor, the secondtransmission path coupler being configured to be moved across a gap ofthe first transmission path coupler, the second transmission pathcoupler further including a circuit configured to control a frequencycomponent at a discontinuity of a signal that occurs when the secondtransmission path coupler is moved across the gap of the firsttransmission path coupler, and to pass a maximum basic frequency of asignal input to the first transmission path coupler, the methodcomprising: generating, by the second transmission path coupler, a firstsignal at timings corresponding to a rising edge and a falling edge ofan input signal input to the first transmission path coupler in a casewhere the input signal is transmitted to a position at which the firsttransmission path coupler and the second transmission path couplerperform an electric field and/or magnetic field coupling, a signal widthof the first signal being substantially in proportion to a length of theelectric field and/or magnetic field coupling of the first transmissionpath coupler and the second transmission path coupler; and inputting thegenerated first signal to the comparator.
 12. A wireless transmissionsystem comprising: a first transmission path coupler includingtransmission lines configured to transmit a signal, one end of each ofthe transmission lines being connected to a send unit, another end ofeach of the transmission lines being connected to a terminatingresistor, the first transmission path coupler being annularly disposed;and a second transmission path coupler including transmission linesconfigured to transmit a signal, one end of each of the transmissionlines being connected to a comparator, another end of each of thetransmission lines being connected to a terminating resistor, the secondtransmission path coupler being configured to be moved across a gap ofthe first transmission path coupler, wherein the second transmissionpath coupler generates a first signal at timings corresponding to arising edge and a falling edge of an input signal input to the firsttransmission path coupler in a case where the input signal istransmitted to a position at which the first transmission path couplerand the second transmission path coupler perform an electric fieldand/or magnetic field coupling, a signal width of the first signal beingsubstantially in proportion to a length of the electric field and/ormagnetic field coupling of the first transmission path coupler and thesecond transmission path coupler, and wherein the second transmissionpath coupler has such a size that a value obtained by subtracting atransmission delay amount corresponding to the gap of the firsttransmission path coupler from the signal width of the first signal issubstantially equal to or greater than a permissible jitter amount of adigital circuit configured to receive a signal output from the secondtransmission path coupler.
 13. A method for controlling a wirelesstransmission system, the wireless transmission system comprising: afirst transmission path coupler including transmission lines configuredto transmit a signal, one end of each of the transmission lines beingconnected to a send unit, another end of each of the transmission linesbeing connected to a terminating resistor, the first transmission pathcoupler being annularly disposed; and a second transmission path couplerincluding transmission lines configured to transmit a signal, one end ofeach of the transmission lines being connected to a comparator, anotherend of each of the transmission lines being connected to a terminatingresistor, the second transmission path coupler being configured to bemoved across a gap of the first transmission path coupler, the methodcomprising: generating, by the second transmission path coupler, a firstsignal at timings corresponding to a rising edge and a falling edge ofan input signal input to the first transmission path coupler in a casewhere the input signal is transmitted to a position at which the firsttransmission path coupler and the second transmission path couplerperform an electric field and/or magnetic field coupling, a signal widthof the first signal being substantially in proportion to a length of theelectric field and/or magnetic field coupling of the first transmissionpath coupler and the second transmission path coupler; and inputting thegenerated first signal to the comparator, wherein a value obtained bysubtracting a transmission delay amount corresponding to the gap of thefirst transmission path coupler from the signal width of the firstsignal is substantially equal to or greater than a permissible jitteramount of a digital circuit configured to receive a signal output fromthe second transmission path coupler.
 14. A non-transitorycomputer-readable storage medium storing instructions that, whenexecuted by a computer, cause the computer to perform a method forcontrolling a wireless transmission system, the wireless transmissionsystem comprising: a first transmission path coupler includingtransmission lines configured to transmit a signal, one end of each ofthe transmission lines being connected to a send unit, another end ofeach of the transmission lines being connected to a terminatingresistor, the first transmission path coupler being annularly disposed;and a second transmission path coupler including transmission linesconfigured to transmit a signal, one end of each of the transmissionlines being connected to a comparator, another end of each of thetransmission lines being connected to a terminating resistor, the secondtransmission path coupler being configured to be moved across a gap ofthe first transmission path coupler, the method comprising: generating,by the second transmission path coupler, a first signal at timingscorresponding to a rising edge and a falling edge of an input signalinput to the first transmission path coupler in a case where the inputsignal is transmitted to a position at which the first transmission pathcoupler and the second transmission path coupler perform an electricfield and/or magnetic field coupling, a signal width of the first signalbeing substantially in proportion to a length of the electric fieldand/or magnetic field coupling of the first transmission path couplerand the second transmission path coupler; and inputting the generatedfirst signal to the comparator, wherein a value obtained by subtractinga transmission delay amount corresponding to the gap of the firsttransmission path coupler from the signal width of the first signal issubstantially equal to or greater than a permissible jitter amount of adigital circuit configured to receive a signal output from the secondtransmission path coupler.